Air carrier captain reported they routinely encounter aircraft with similar sounding call signs.

Attributes
ACN	1507142
Time
Date	201712
Local Time Of Day	0001-0600
Place
Locale Reference	WSJC.ARTCC
State Reference	FO
Environment
Light	Dawn
Aircraft 1
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Procedural Other / Unknown

Narrative:

Similar call signs continue to be a problem after years of complaining about this. Singapore ATC pointed out confusion over similar call signs both on frequency. This is something that consistently happens out here. I have written safety reports in the past about this problem. With a language barrier already; why is this practice continued? Stop assigning similar call signs in the same area at the same time of day.

Original NASA ASRS Text

Title: Air carrier Captain reported they routinely encounter aircraft with similar sounding call signs.

Narrative: Similar call signs continue to be a problem after years of complaining about this. Singapore ATC pointed out confusion over similar call signs both on frequency. This is something that consistently happens out here. I have written safety reports in the past about this problem. With a language barrier already; why is this practice continued? Stop assigning similar call signs in the same area at the same time of day.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.